Seepage and flood water levels are “definitely higher than average,” Lewis reported, in the wake of the water hitting just under six metres at the Mission gauge when the river peaked recently.

So they’ve been going at it hard.

“We’ve made several thorough aerial, and many ground applications this season in an effort to reduce adult mosquito annoyance,” Lewis said.

They use a granular bacterial larvicide called Bti. It is dropped from a helicopter, or ladled in by hand into the water. Technicians will wade or paddle into swampy areas to treat them.

When the flood water rushes into the dry areas each spring, it can rehydrate a lot of mosquito eggs.

Lewis has been chasing and monitoring mosquitoes in the Fraser Valley since 1989. He said in a 2011 interview with the Progress that 1999 was the worst year he’d ever seen.

Some years, the larval density is higher than others, and can add to the nuisance level.

The annoyance will come from the blood-seeking mosquitoes that they didn’t manage to kill early in the season. The environmentally friendly Bti product specifically targets the mosquito in its larval stage before it can fly.

For many years now, as a matter of policy, the FVRD does not and will not conduct aerial fogging or spraying of residual chemicals to kill flying adult mosquitoes.

Wearing DEET-based repellent, and long-sleeved, light-coloured, loose-fitting clothing is recommended, if out in the mosquito-dense times of dusk and dawn.

Morrow BioScience field crews are “actively monitoring” all areas in the FVRD, Lewis said, and the hotline calls get returned within 24 hours. Accessible locations of standing water can be treated.